REU/LTER: Insect Fossils and Late Quaternary Environments of Western Texas

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Knowledge of Late Quaternary environments of the desert southwest has expanded greatly in the past twenty years, due mostly to the introduction of paleobotanical studies of packrat middens. Paleoecological reconstructions of the Chihuahuan Desert regions of western Texas have been developed by Van Devender (1985) for the past 40,000 years, documenting a series of vegetational responses to environmental changes during and after the Wisconsin Glaciation. Van Devender has made a series of 110 insect fossil assemblages available for detailed investigation. In this research, these assemblages will be used to test hypotheses concerning modern analogs for past insect faunal assemblages, the relative rate of insect response to environmental change in comparison to that of the vegetation, and the origins of the modern Chihuahuan Desert insect fauna. In addition, the taphonomy of insect fossils in packrat middens will be examined and modern insect habitat and distribution data will be collected. Experiments on live-trapped packrats will test their acceptance and/or preference for various large-sized beetle species. The insect fossil samples cover the same time span as the paleobotanical record, and derive from the same midden samples. This provides site-by-site and sample-by-sample paleobotanical data and radiocarbon chronologies for correlation with insect fossil data.